What is a pack-year?
A pack-year is a standard unit used to describe a person’s cumulative smoking history. One pack-year equals smoking an average of one pack (20 cigarettes) per day for one year. It’s commonly used as a reference figure when discussing smoking history and general risk trends at a population level.
How this calculator works
The formula is straightforward: divide your average cigarettes smoked per day by 20 to get packs per day, then multiply by the number of years you smoked. For example, smoking 10 cigarettes a day for 10 years equals 5 pack-years (0.5 packs/day x 10 years).
This calculator provides a general historical estimate only and does not account for periods of quitting, varying consumption over time, or individual health risk, which depends on many factors. It is for general informational and educational purposes only and is not a substitute for professional medical assessment.